serial: atmel_serial: add poll_get_char and poll_put_char uart_ops

Permits using KGDB over the console with the atmel_serial driver.

[akpm@linux-foundation.org: s/barrier/cpu_relax/]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/serial/atmel_serial.c

@@ -1213,6 +1213,24 @@ static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser)
 	return ret;
 }
 
+#ifdef CONFIG_CONSOLE_POLL
+static int atmel_poll_get_char(struct uart_port *port)
+{
+	while (!(UART_GET_CSR(port) & ATMEL_US_RXRDY))
+		cpu_relax();
+
+	return UART_GET_CHAR(port);
+}
+
+static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
+{
+	while (!(UART_GET_CSR(port) & ATMEL_US_TXRDY))
+		cpu_relax();
+
+	UART_PUT_CHAR(port, ch);
+}
+#endif
+
 static struct uart_ops atmel_pops = {
 	.tx_empty	= atmel_tx_empty,
 	.set_mctrl	= atmel_set_mctrl,
@@ -1232,6 +1250,10 @@ static struct uart_ops atmel_pops = {
 	.config_port	= atmel_config_port,
 	.verify_port	= atmel_verify_port,
 	.pm		= atmel_serial_pm,
+#ifdef CONFIG_CONSOLE_POLL
+	.poll_get_char	= atmel_poll_get_char,
+	.poll_put_char	= atmel_poll_put_char,
+#endif
 };
 
 /*